Dietary and nutrition interventions for the therapeutic treatment of chronic fatigue syndrome/myalgic encephalomyelitis: a systematic review N. Campagnolo, S. Johnston, A. Collatz, D. Staines & S. Marshall-Gradisnik. Journal of Human Nutrition and Dietetics (2017) doi: 10.1111/jhn.12435

Background
Chronic fatigue syndrome (CFS), or myalgic encephalomyelitis (ME), is a chronic, disabling illness characterised by unexplained fatigue for at least 6 months along with a wide range of consistent symptoms, such as short-term memory difficulties or problems concentrating, muscle and/or joint pain and headaches.

It is estimated around 250,000 people in the UK have CFS/ME (NHS Choices 2015). It's more common in women than men and usually develops when people are in their early 20s to mid-40s. Children can also be affected, typically between the ages of 13 and 15 years.

CFS/ME patients also often report gastrointestinal symptoms (e.g. nausea, vomiting and pain) or food intolerances (e.g. wheat and dairy) and many may change their diet or take a nutritional supplement in an attempt to reduce fatigue with some self-report of improvement in symptoms. It is unclear however whether dietary manipulation can change outcomes in CFS/ME.

Study objective
The authors of the study aimed to review currently available research that investigated nutrition interventions for managing symptoms in patients with CFS/ME.

Study design
A systematic search of databases was completed for studies (including observational and randomised controlled trials) on nutrition intervention in adults published between 1994 and 2016. Studies were included if they evaluated the effectiveness of food and/or nutritional supplement on the primary outcome, fatigue in CFS/ME patients, diagnosed according to recognised criteria. Studies were also included if they evaluated other secondary outcomes, such as quality of life, physical activity levels and/or psychological wellbeing. Studies that used multi-treatments (e.g. nutrition and pharmaceutical treatment) and case studies were excluded. Data from eligible studies were extracted.

Main findings
Seventeen studies, of reasonable quality were included in the systematic review, with 14 different interventions in total evaluated. The vast majority of studies looked at the effect of nutrition supplementation compared to placebo. None of the included studies looking at the effect of modifying participants’ diets.

  • Fatigue – Although many interventions did not show a benefit, a number of small trials reported a significant reduction in fatigue, measured using a variety of instruments (e.g. Multidimensional Fatigue Inventory, Visual Analogue Scales, Fatigue Index Symptom Questionnaire). These nutrition interventions included:
    • Nicotinamide adenine dinucleotide hydride (NADH) + coenzyme Q10 (n = 39);
    • Guanidinoacetic acid (GAA) (n = 21);
    • High cocoa liquor/polyphenol-rich chocolate (15 g of 85% cocoa solids bar three times daily; n = 10);
    • Probiotic bacteria supplement (n = 15).
  • Psychological wellbeing - Three studies observed an improvement in psychological wellbeing, with outcomes including a significant decrease in anxiety symptoms after probiotic supplementation (n = 19) and a significant decrease in anxiety after supplementation with L-carnitine (n = 28) and polyphenol-rich chocolate (n = 10).
  • Quality of life – RCTs showed that supplementation with BioBranTM MGN-3 (produced by breaking down rice bran with enzymes from the Shitake mushroom) improved quality of life on the social wellbeing subscale (n = 37), and GAA supplementation also had a significant improvement on physical and mental common scores of quality of life (n = 21). The same effect was also observed in two comparative studies after supplementation of L-carnitine (n = 28), and two other forms of L-carnitine (acetyl-L-carnitine and propionyl-L-carnitine; n = 30).
  • Physical activity level – no studies reported an improvement in physical activity level. One study did report a significant improvement in isometric quadriceps strength and VO2 max after patients took GAA for 3 months (n = 21).

Author conclusions
There currently isn’t enough evidence for the use of nutritional supplements and elimination/modified diets to help relieve symptoms of CFS/ME. Therefore, further research is necessary.

Limitations
The number of studies investigating nutritional intervention on CFS/ME symptoms is very limited. In addition, within the included studies the mean sample size was small (24 participants), and interventions typically did not have long-term follow up (>6 months). Studies varied in the way that they measured symptoms such as fatigue, which makes it difficult to compare the findings and apply them to the general CFS/ME population. Additionally, a common criticism of the Fukuda (1994) case definition used to define CFS/ME in the majority of studies is that it includes a combination of broad nonspecific symptoms. Thus it is less likely to define a homogeneous patient population.  None of the studies described if or how they assessed and analysed participants’ diets at baseline and throughout the intervention, therefore any changes in the diet that might have occurred could have affected the results.

Relevance
The impact on the quality of life for individuals with CFS/ME can be significant and there is currently no cure or widely accepted treatment, therefore any route to improving symptoms and quality of life warrants further investigation. There are no current recommendations for the use of nutritional supplements and/or modified diets to relieve CFS/ME symptoms, and this review provides confirmation that there is insufficient evidence to change this.  Until further evidence becomes available, patients with CFS/ME should aim to consume a healthy, balanced diet as per dietary guidelines for the general population, but supplements can be given when nutrient deficiencies, food intolerance or GI conditions have been diagnosed by a health professional.

References
NHS Choices (2015) Chronic fatigue syndrome. Available at: http://www.nhs.uk/conditions/Chronic-fatigue-syndrome/Pages/Introduction.aspx